When manufacturing sterile medical products, especially filter modules/dialyzers, it has to be ensured that the product remains sterile until use with a patient or use within the scope of treatment. For this purpose, it has to be guaranteed that either the sterile barrier is applied to the product or that the package forms a sterile barrier against the environment which remains intact over the shelf-lifetime stated on the product when realistic storage conditions are assumed.
Filter modules/dialyzers are designed as to their appearance exclusively with respect to requirements in terms of manufacture and application. It is obvious that special requirements to the filter module/dialyzer package are derived from this form. As regards the package, especially standardized, projecting and sharp-edged connectors on the filter module/dialyzer, edges on the filter module/dialyzer and on protection caps of the filter module/dialyzer constitute a problem.
Known packages for medical products, in particular for filter modules/dialyzers, primarily consist of a plastic or aluminum hose or a side-sealed bag (as primary package) as well as of a tray made from plastic material, paperboard or cast fiber and, where necessary, an outer cardboard box (as secondary package). Especially, the tray usually has a shape which substantially corresponds to the shape of the products packed in the primary package so that a kind of form closure is given with which a position-stable package is strived for.
Several medical products, especially filter modules/dialyzers, may have to be sterilized in oxygen-free conditions. This means that at the time of sterilization the interior of the primary package has to be completely oxygen-free. As a rule, this is materialized by absorbing the oxygen by an appropriate carrier, a so-called getter. The carrier material may be iron powder or a polymer, for example. The absorber may be supplied to the primary package as a sachet, as it is called, or may be contained in the structure of the packaging material (film).
It is a considerable drawback that the binding of molecular oxygen in the closed-off system of the primary package results in a reduction of volume and, respectively, a vacuum (in non-deformable environment). Known packaging systems are not dimensionally stable, as a consequence the volume thereof is reduced corresponding to the binding of oxygen after closing the package in an uncontrollable manner. Such reduction of volume of the primary packages enables relative movements between packed filter modules/dialyzers inside the secondary package as well as between packed filter modules/dialyzers and the secondary package, wherein said relative movements in turn may result in damage of the sterile barrier.
In known filter module/dialyzer packages the afore-described problems of relative movements due to a reduction of volume during sterilization and ensuing possible damage of the sterile barrier is counteracted by the use of appropriately thick films and/or an oxygen-reduced atmosphere during a packaging process. Both processes have the drawback of entailing high material and processing costs, respectively. It is another drawback that reductions of volume by providing an oxygen-reduced atmosphere in the packaging process cannot be completely excluded, as such package, especially a filter module/dialyzer package must be guaranteed to be 100% oxygen-free. As a result, use of an absorber and reductions of volume resulting therefrom are indispensable. Thicker packaging materials of higher mechanical load capacity for the primary package increase the product costs and still cannot ensure 100% safety to the integrity of the sterile barrier.